AbstrakPenelitian ini bertujuan untuk memvalidasi metode analisis siklamat secara spektrofotometri dan turbidimetri dalam sampel minuman jelly drink rasa mangga secara spektrofotometri dengan pereaksi hipoklorit, spektrofotometri ultra violet (tanpa pereaksi) dan turbidimetri. Kurva kalibrasi larutan standar natrium siklamat pada metode spektrofotometri dengan pereaksi hipoklorit, spektrofotometri UV (tanpa pereaksi), dan turbidimetri berbentuk linier. Daerah kerja masing-masing metode secara berturut-turut pada konsentrasi (211,08); (16,434); dan (1,852-6,172) ppm. Batas deteksi masing-masing metode secara berturut-turut sebesar 53,6028; 0,5833; dan 0,2723 ppm. Batas kuantitasi masing-masing metode secara berturut-turut sebesar 66,9948; 1,9443; dan 0,8068 ppm. Metode analisis siklamat secara spektrofotometri dengan pereaksi hipoklorit mempunyai presisi dan akurasi yang baik, sementara metode analisis siklamat secara spektrofotometri UV mempunyai presisi baik dan akurasi kurang baik. Sedangkan metode analisis siklamat secara turbidimetri mempunyai presisi dan akurasi kurang baik. (211.36-747.08); (16.000-146.434); and (1.8521-6.1717) ppm. The detection limit of each method successively were 53.6028; 0.5833; and 0.2723

The study describes the bacth experiment on technical diret red dyes removal from aqueos solution which use cellulose acetat prepared from Ananas comosus leaves. The Adsorption investigations were carried out in various of time, adsorbent mass, adsorbate concentration, and temperature. The adsorption kinetics followed a pseudo second order reaction. The equilibrium adsorption data was best presented by the Freundlich isotherm. The calculated thermodynamic parameters indicate that the ongoing adsorption process was endothermic and non-spontaneous in nature.

The electrochemical sensor based on polyeugenol/polyvinyl alcohol-modified graphite electrode, i.e., GEPVAEu, was prepared for the determine the hydroquinone (HQ). The electrode was modified through an electropolymerization process. The modified electrode showed excellent performance for the HQ sensor in phosphate buffer solution (PBS) of pH 7.0 by the cyclic voltammetry method. The impact of scan rates confirmeds that the redox electrochemical behavior of HQ was a diffusioncontrolled electrochemical process on the GEPVAEu electrode. The cyclic voltammetry results informed that GEPVAEu hads excessive electrocatalytic activity towards HQ oxidation if compared to the unmodified graphite electrode. The GEPVAEu electrode was able to determine the HQ concentration across two linear response stages from 3.67-103.27 and 140.90-482.11 µM with the sensitivities of 4.13 and 1.02 A M-1 , respectively. The LOD and LOQ values were 2.27 M and 6.87 M, respectively, which were remarkable. Therefore, the GEPVAEu electrode has the potential to be used as an electrochemical sensor for the HQ.

Graphite electrode was modified by electropolymerization of eugenol in alkaline medium by cyclic voltammetry. The polyeugenol-graphite modified electrode (GEEU) was than used for the determination of hydroquinone (HQ) at phosphatbuffer solution (PBS) of pH 7.0 by cyclic voltammetry technique. The performance of this modified has shown excellent electrocatalytic activity toward HQ than an unmodified electrode (GE). The oxidation and reduction peak separation (ΔE) has been decreased from 0.309 V to 0.228 V. In addition, the effect of scanratesindicate that redox electrochemical behaviour of HQ is diffusion controlled electrochemical process on GEEU. Under experimental, the oxidation peak current(I p ) increases linearly with concentration (C) of HQ ranged from 1.42 –101.07μMat the linear regression equatian of I p = 3.86C + 355.20 (νA, R2 = 0.9989). On the other hand, the oxidation peak current also increases linearly at ranged from 136.67 – 480.50 μM at the linear regression equation of I p = 1.69C + 559.72 (μA, R2 = 0.9956). The LOD and LOQ were measured at a lower concentration of HQ,1.44μM and 4.37μM, respectively. Moreover, the proposed modified has been successfully applied to the determination of HQ in the cosmetic sample with satisfactory recoveries.